1 /* Copyright (c) 2014, Google Inc. 2 * 3 * Permission to use, copy, modify, and/or distribute this software for any 4 * purpose with or without fee is hereby granted, provided that the above 5 * copyright notice and this permission notice appear in all copies. 6 * 7 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 8 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 9 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 10 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 11 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION 12 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN 13 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ 14 15 #include <openssl/aead.h> 16 17 #include <string.h> 18 19 #include <openssl/cipher.h> 20 #include <openssl/err.h> 21 22 #include "internal.h" 23 24 25 size_t EVP_AEAD_key_length(const EVP_AEAD *aead) { return aead->key_len; } 26 27 size_t EVP_AEAD_nonce_length(const EVP_AEAD *aead) { return aead->nonce_len; } 28 29 size_t EVP_AEAD_max_overhead(const EVP_AEAD *aead) { return aead->overhead; } 30 31 size_t EVP_AEAD_max_tag_len(const EVP_AEAD *aead) { return aead->max_tag_len; } 32 33 int EVP_AEAD_CTX_init(EVP_AEAD_CTX *ctx, const EVP_AEAD *aead, 34 const uint8_t *key, size_t key_len, size_t tag_len, 35 ENGINE *impl) { 36 if (!aead->init) { 37 OPENSSL_PUT_ERROR(CIPHER, EVP_AEAD_CTX_init, CIPHER_R_NO_DIRECTION_SET); 38 ctx->aead = NULL; 39 return 0; 40 } 41 return EVP_AEAD_CTX_init_with_direction(ctx, aead, key, key_len, tag_len, 42 evp_aead_open); 43 } 44 45 int EVP_AEAD_CTX_init_with_direction(EVP_AEAD_CTX *ctx, const EVP_AEAD *aead, 46 const uint8_t *key, size_t key_len, 47 size_t tag_len, 48 enum evp_aead_direction_t dir) { 49 if (key_len != aead->key_len) { 50 OPENSSL_PUT_ERROR(CIPHER, EVP_AEAD_CTX_init_with_direction, 51 CIPHER_R_UNSUPPORTED_KEY_SIZE); 52 ctx->aead = NULL; 53 return 0; 54 } 55 56 ctx->aead = aead; 57 58 int ok; 59 if (aead->init) { 60 ok = aead->init(ctx, key, key_len, tag_len); 61 } else { 62 ok = aead->init_with_direction(ctx, key, key_len, tag_len, dir); 63 } 64 65 if (!ok) { 66 ctx->aead = NULL; 67 } 68 69 return ok; 70 } 71 72 void EVP_AEAD_CTX_cleanup(EVP_AEAD_CTX *ctx) { 73 if (ctx->aead == NULL) { 74 return; 75 } 76 ctx->aead->cleanup(ctx); 77 ctx->aead = NULL; 78 } 79 80 /* check_alias returns 0 if |out| points within the buffer determined by |in| 81 * and |in_len| and 1 otherwise. 82 * 83 * When processing, there's only an issue if |out| points within in[:in_len] 84 * and isn't equal to |in|. If that's the case then writing the output will 85 * stomp input that hasn't been read yet. 86 * 87 * This function checks for that case. */ 88 static int check_alias(const uint8_t *in, size_t in_len, const uint8_t *out) { 89 if (out <= in) { 90 return 1; 91 } else if (in + in_len <= out) { 92 return 1; 93 } 94 return 0; 95 } 96 97 int EVP_AEAD_CTX_seal(const EVP_AEAD_CTX *ctx, uint8_t *out, size_t *out_len, 98 size_t max_out_len, const uint8_t *nonce, 99 size_t nonce_len, const uint8_t *in, size_t in_len, 100 const uint8_t *ad, size_t ad_len) { 101 size_t possible_out_len = in_len + ctx->aead->overhead; 102 103 if (possible_out_len < in_len /* overflow */) { 104 OPENSSL_PUT_ERROR(CIPHER, EVP_AEAD_CTX_seal, CIPHER_R_TOO_LARGE); 105 goto error; 106 } 107 108 if (!check_alias(in, in_len, out)) { 109 OPENSSL_PUT_ERROR(CIPHER, EVP_AEAD_CTX_seal, CIPHER_R_OUTPUT_ALIASES_INPUT); 110 goto error; 111 } 112 113 if (ctx->aead->seal(ctx, out, out_len, max_out_len, nonce, nonce_len, in, 114 in_len, ad, ad_len)) { 115 return 1; 116 } 117 118 error: 119 /* In the event of an error, clear the output buffer so that a caller 120 * that doesn't check the return value doesn't send raw data. */ 121 memset(out, 0, max_out_len); 122 *out_len = 0; 123 return 0; 124 } 125 126 int EVP_AEAD_CTX_open(const EVP_AEAD_CTX *ctx, uint8_t *out, size_t *out_len, 127 size_t max_out_len, const uint8_t *nonce, 128 size_t nonce_len, const uint8_t *in, size_t in_len, 129 const uint8_t *ad, size_t ad_len) { 130 if (!check_alias(in, in_len, out)) { 131 OPENSSL_PUT_ERROR(CIPHER, EVP_AEAD_CTX_open, CIPHER_R_OUTPUT_ALIASES_INPUT); 132 goto error; 133 } 134 135 if (ctx->aead->open(ctx, out, out_len, max_out_len, nonce, nonce_len, in, 136 in_len, ad, ad_len)) { 137 return 1; 138 } 139 140 error: 141 /* In the event of an error, clear the output buffer so that a caller 142 * that doesn't check the return value doesn't try and process bad 143 * data. */ 144 memset(out, 0, max_out_len); 145 *out_len = 0; 146 return 0; 147 } 148 149 int EVP_AEAD_CTX_get_rc4_state(const EVP_AEAD_CTX *ctx, const RC4_KEY **out_key) { 150 if (ctx->aead->get_rc4_state == NULL) { 151 return 0; 152 } 153 154 return ctx->aead->get_rc4_state(ctx, out_key); 155 } 156
